Expendable pallets having molded plastic feet are known. Additionally, various configurations for attaching the feet to the platforms are known. The purpose of designing and intending a pallet to be expendable is to provide pallets which are lower in cost than conventional wooden pallets, yet are capable of supporting substantial weight. In spite of their low cost, some reuse is expected and therefore durability is also desirable and possible in expendable pallets.
One approach in designing expendable pallets has been to use molded plastic feet attached to a platform. The molded plastic feet provide the capability of the pallets to support substantial weight. The platform may be of lightweight material, such as cardboard, to maintain the pallet's configuration and to reduce the weight of the pallet.
U.S. Pat. No. 3,610,172 discloses molded plastic feet for an expendable pallet. There, a foot consists of a circular tapered cup portion having a flange extending outside the cup from the top and an annular ridge near the top. An open circular locking ring consists of a flange of the same size as that on the cup but with a downwardly depending body portion rim which extends into the cup. The body portion rim has an annular groove which cooperates with the annular ridge inside the cup to lock the two components together. The foot is inserted into a hole in the platform and the edges of the hole are sandwiched between the ring flange and the cup flange. Similarly, French Patent No. 2 411 136 shows a foot having a circular tapered cup portion and a locking ring with a downwardly depending body portion rim. However, such locking ring rim portion is longer than that of the U.S. Pat. No. 3,610,172 patent and has a plurality of raised annular ridges which cooperate with a plurality of annular grooves in the cup to lock the two pieces together.
U.S. Pat. No. 3,598,065 discloses a circular foot which is circumscribed at the top with a slot. The foot, which is tapered, is inserted into a hole and forced therethrough until the edges of the hole snap into the slot to secure the foot in the hole. No locking ring is needed. U.S. Pat. No. 3,664,272 shows another foot which is secured without a locking ring. A flange projects outwardly from the upper end of the foot and engages the upper surface of the platform. The foot is retained by lugs which project outwardly from the foot for engagement with the underside of the platform.
Yet another foot is disclosed by U.S. Pat. No. 4,425,852. There, the foot comprises a circular cup and includes a flange which engages the upper surface of the platform when the cup is inserted through a suitable hole. The cup has a circumferentially ridged shoulder portion which extends below the underside of the platform when the cup is inserted in its hole. A locking ring has a flange similar to the one on the cup which engages the underside of the platform. The ring has an annularly ridged skirt portion which cooperates with the ridged shoulder portion on the cup to lock the two pieces together, sandwiching the platform between them.
However, there are several disadvantages encountered in various ones of such prior art devices. For example, because the cardboard is susceptible to expansion and tearing, feet such as are disclosed in the '065 patent may too easily fall off. In others of the prior art devices the feet have a tendency to fall off after considerable weight is place on them because of the temporary physical deformities which occur when the cup is subject to great weight or such weight may cause the portions of the feet to come apart.